[tex]dane:\\m = 20 \ kg\\h = 30 \ cm =0,3 \ m\\g = 10\frac{m}{s^{2}}\\szukane:\\v = ?\\\\Rozwiazanie\\\\Z \ zasady \ zachowania \ energii\\\\E_{p} = E_{k}\\\\mgh = \frac{mv^{2}}{2} \ \ /\cdot\frac{2}{m}\\\\v^{2} =2gh\\\\v = \sqrt{2gh}\\\\v = \sqrt{2\cdot10\frac{m}{s^{2}}\cddot0,3 \ m}\\\\v = \sqrt{6\frac{m^{2}}{s^{2}}[/tex]
[tex]\underline{v\approx2,45\frac{m}{s}}[/tex]
